Method of delivering liquids fkom wells



Dec. 3, 1929. G, BLOW 1,737,635

METHOD oF DELIVERING LIQUIDS FROM WELLS vFiled Feb. 24, 1927 2 Sheets-Sheet l am ufo Dec. 3, 1929. G. BLow 1,737,635

METHOD OF DELIVERING LIQUIDS FROM WELLS Filed Feb. 24, 1927 2 Sheets-Sheet 2 Patented Dec. 3, 1929 PATENT OFFICE GEORGE BLOW, OF KNOXVILLE, TENNESSEE METHOD OF DELIVERING LIQUIDS FROM WELLS Application led February 24, 1927. Serial No. 170,600.

This invention relates to the delivery of oil from oil wells, and has for its object to decrease the cost of such delivery and increase the per diem amount of oil delivered from the wells.

Oil is delivered from oil wells either by flow of the oil from the well by reason of the natural pressure in the sand; or, when this natural pressure, either gas or hydrostatic, is

l0 insuicient to cause the oil to flow from the well, a head of oil is allowed to rise in the well, which head is periodically pumped off or the oil is continuously delivered from the well by mechanical pumping.

All wells which flow by natural gas pressure when first brought in, later How by heads and then cease flowing, and another object of the present invention is to cause wells that have ceased to flow by natural gas pressure to again flow under the natural gas pressure of the Well, regardless of the depth of the well and the lowest available gas pressure.

In nearly all oil wells the oil and gas is caused to flow into the well b reason of the natural gas pressure exerte in the sandL When a well reaches the stage where it heads up, the head of oil as it rises in the well offers a resistance to the natural gas pressure in the sand, and as this resistance increases, due to the rise of the head, the inflow of oil tothe Well decreases; and, when the pressure of the head in the well equals the natural gas pressure in the sand, inflow of oil to the well ceases until the head of oil in the Well is pumped ofi". A further object of the present` invention is to secure a continuous flow of oil into wells that have ceased to flow under natural gas pressure in the sand by eliminating the formation of heads in the well and delivering the oil therefrom under such natural gas pressure of the sand. By such continuous flow under natural pressure, unresisted by back pressure due to heads in the well, the amount of oil flowing into the well,

per diem, is increased.

The above and other objects are accomplished by placing in the well a staged gas lift, the stages of which are so spaced as to 60 operate under the lowest gas pressure that may become available in the well, and then sealing the well except for the oil delivering outlet of the lift and the gas vent therefrom, which vent is provided with a loaded vent valve for maintaining the desired or necessary gas pressure in the Well, and operating the lift by the use of the natural gas of the Well. The well being sealed as indicated above, the gas in the well is under compression by the natural gas pressure in the sand, and it will therefore be apparent that the delivery of the oil by the lift is really due to this natural gas pressure. By this means Wells which, when first brought in, flowed by natural pressure and later ceased to thus fiow and had to be pumped by heads are caused to deliver their oil without mechanical pumping and solely by utilization of the natural gas pressure. By sealing an oil well having a staged gas lift therein and utilizing the natural gas pressure of the well to operate the lift, the expense of installing compressing machinery and connections therefrom to the lift, and the expense of operating the compressing machinery are wholly eliminated. The gas is vented against an adjustable resistance, preferably secured by means of a loaded vent valve. This adjustable resistance to the venting of the gas through the lift is of much importance since it makes it possible to utilize the available gas pressure eiliciently and without waste, and also makes it possible to install the apparatus so that it may operate with any ultimate low gas ressure though the initial gas pressure may Ee much greater.

The apparatus employed in practicing the invention may vary in detail withncertain limits, but, enerally stated, it comprises a staged gas li t, the operating gas for which is the natural gas of the well. The stages of the lift are preferably somewhat closely spaced, to the end that it may freely operate even if the well affords but low submergence and low gas pressure, and preferably each stage consists of a riser ipe and a vent pipe enclosed in a section of pipe of less diameter than the well, the gas from the well being admitted to the bottom part of each riser pipe through a suitable port. The vent pipes of the several stages are in open communication with each other and together constitute the vent of the entire staged gas lift, which is provided with the loaded vent valve at the surface.

In case a well has ceased to flow by natural gas pressure and a head of oil has accumulated in the well, and` there is not suicient natural gas made by the well to operate the gas lift, the well may be closed and air or other gas under pressure introduced into the well. In this case the gas lift acts as a staged air lift pump, and by its action the column of liquid constituting the head may be lowered so that the combined pressure of the lowered column and the air is less than that causing vthe flow of liquid into the well. Undcr these conditions the'interval between the stages is determined by the air pressure utilized which combined with the pressure of the lower column of liquid, is less than the pressure causing the inflow of liquid to the well.- By this means, wells that do not make enough natural gas to operate a staged gas lift may, nevertheless, be caused to flow continuously, and without the forma-tion of a head or column of oil that would slow up or stop` the flow into the well under the pressure of the normal stand of liquid on the producing stratum in the Well.

The usual or any suitable means may be employed to introduce the compressed air or other gas into the sealed well, as through a valved pipe entering the well through sealing ca Ine form of apparatus that may be employed in practiclng the invention is illus` trated in the accompanying drawings, but it is to be expressly understood that such'drawings are not desi ned to define the' limits of the invention, refrence being had to the appended claims for this purpose.

In said drawings- Fig. 1 is a vertical section through a sealed oil well and having the staged gas lift in position therein;

Fig. 2 is a broken diagrammatic view of a part of the gas lift; Y

Fig. 3 is a broken, partly sectional detail of one part of the preferred apparatus; and

Fig. 4 is a horizontal section on the line 4-4 Fig. 3.

In said drawings, in which like reference numerals indicate like parts throughout the several views, 1 indicates an oil well having lthe usual or any suitable easing, not shown, and of any depth, and 2 indicates a pipe or shell of less diameter than the well formed of sections 2', which sections are connected by couplings 3. This pipe or shell extends from near the bottom of the well to the top thereof, where it is provided with a delivery end 4, ,delivering into any suitable tank 5. The top of the Well is closed by any suitable seal as a cap 6 surrounding the shell 2 and held in place by a collar 7 on said shell.

Within the shell 2 is a series of staged gas lifts, the construction of which is clear ly illustrated in Fig. 2, in which each of the couplings 3 is shown as provided with a horizontal diaphragm 8 and with a port or ports 9 leading from the interior of the well to the interior of the shell 2. Supported on the diaphragm 8 of each coupling 3, and in an opening passing through said diaphragm, is a section of pipe 10 open at its bottom, as shown, and capped at its top l1 and having below the top a plurality of ports 12. A-pipe 13, open at both ends, passes through the diaphragms 8 of each of the couplings 3, the lower end of said pipe being adjacent to the diaphragm just below the one through which the pipe passes, and the upper end of said pipe being just under the diaphragm above the one through which the pipe passes and preferably on about a level with the ports 12 in the pipes 10. The pipes 13 have their lower ends preferably supported on brackets 14 .formed on the interior Walls of the couplings 3 above each of the diaphragms 8, and through which brackets the ports 9 are preferably' formed, said ports terminating just at the base of the pipes 13.

Referring now to Fig. 1, the iwermost pipe 13 is shown as projecting from the shell 2 downward for a suitac-.-... distance into the oil 15 in the bottom of the well, and at the top of the lift one of the pipes 10 is shown projecting from the shell and provided with a loaded vent valve 16, said valve being so constructed that the load thereon may be adjusted at will.

The preferred form of cou ling 3 is shown in detail in Figs. 3 and 4. T e pipes 13 pass entirely through the diaphragm 8 and are preferably made in screw-threaded sections, as shown at theleft hand side of Fig. 3, and are coupled together by a sleeve coupling 13', a suitable packing collar 17 being screwthreaded onto one of the sections above the diaphragm 8 so as to etl'ectually close the openlng through said diaphragm. The other pipe 13 1s open in its lower end and screwthreaded at 18 into the bracket 14, see Fig. 4, which bracket is provided with an opening 19 for this purpose. As shown in Fig. 4, a plurality of ports 9 communicate from the exterior of the coupling to the interior of this opening 19 and, as will be understood from an inspection of Fig. 3, connnunicate with the opening 19 in the bracket just below the bottom of the ipe 13 which is carried by said bracket. aid ports 9 are pref- 125 erably controlled by check valves 20, and the ports are protected by outwardly pro jecting shoulders 21.

In practicing the method of the invention, the well being sealed at its top, oil will flow into the well under the natural pressure inl the sand, and gas will accumulate in the well above the oil and be put under compression therein by its natural pressure. 'The extent of this pressure on the gas accumulated in the Well can be limited and controlled by the loaded vent valve 16 and also by a valve controlled vent through the seal of the well, the latter not being shown in the drawings. The lower end of the pipe 13, Fig. 1, contains the oil and is submerged in the oil to a proper distance and is provided with ports 22, Fig. 1, normally below the surface of the oil in the well. As the ressure of the gas in the well lowers the sur ace of the oil therein below the uppermost of the ports 22, the gas under pressure enters the pipe 13 through ports 22 and mingles with the column of oil therein in the form of gas bubbles, thereby lightening said column of4 oil and causing it to rise in the pipe 13 by which it is carried upward through the first diaphragm of the couplings 3 and delivered at the top of the riser ipe 13 and overflows within the shell 2 an is caught by the diaphragm through which the riser pipe passes. This continues until the oil in the section above the diaphragm reaches approximately the level of the ports 12 in the pipes 10. As the combined oil and gas escape from the top of the riser pipes 13, the gas separates from the oil and passes upward through the next diaphragm 8, being conducted through the vent pipe 10 at the top of which pipe it passes out through the ports 12 and upward into the next vent pipe 10, and so on to the top where the vent valve 16 is located. When the oil in the shell 2 above the diaphragm 8 has reached a height to a'ord the proper submergence to the next riser pi e 13, gas entering the ports 9 rises through t e oil in said pipeand causes it to rise tothe top of this second riser pipe by which it is delivered to the shell 2, above the second diaphragm. This action is re cated at each diaphragm or stage of the li t. Should the oil be delivered through one riser pipe more rapidly than it is carried off through the next succeeding riser pipe, so that the oil in any given stage rises as high as the ports 1'2 of the pipes 10, the oil returns through said pipe 10 to the next lower stage, but no farther, since it necessarily falls upon the capped top of the next lower section 10 of the vent pipe. Each of the stage couplings has a riser pipe passing there through and delivering oil thereabove, where it is caught and retained until it suiciently submerges the bottom portion of the next riser pipe carried by the coupling, which riser in turn delivers the oil above the next diaphragm. This action is repeated at each stage of the lift, and in each stage the energy causing the oil to rise to the next stage 1s that of the natural gas confined in the well. The

pipes 10 together constitute, in effect, a vent conduit whereby the gas separating from the oil at the top of each riser pipe is permitted to rise to the vent valve 16.

Before closing in the well all of the stages may be primed by suitable connections in the discharge pipe 4 whereby liquid is introduced through the uppermost pipe 13 and allowed to flow downward successively from stage to stage until every stage is filled with liquid within the shell 2 and above the diaphragm 8, said liquid being retained in each stage by the ball valves 20. Thus the proper submergence is provided for each stage, and since the stages are equal in height the pressure against the entrance of gas from the well into each stage is equal throughout the depth of the well.

The distance between the several diaphragms of the couplings may vary within a wide range, depending upon the natural gas pressure in the well. Where the gas pressure is high, it will act to elevate the oil through a greater distance than Where the gas pressure is low, and, hence, in a well of high gas pressure the spacing between the diaphragms may be much greater than when the natural gas pressure in the well is low. Preferably, however, the spacing of the dia hragrns 1s made short enough to render the evice operative at any ultimate low gas pressure, since if it is operative at the lowest available gas pressure it will be operative at all high gas pressures through control of the back pressure in the vent pipe, and therefore may be placed in the well while the gas pressure is high and will still continue to operate without change as the gas pressure decreases.

lVhen the well is in operation, the oil will be continuously delivered through the staged gas lift by the natural gas pressure in the well, thus preventing the collection of any considerable column or head of oil in the well which would offer resistance to the iniow of the oil under the natural gas pressure in the sand, and by controlling pressure of the gas in the well, the combined resistance of the gas in the well and the low column of oil in the well can be maintained at a pointless than the natural pressure in the sand, and thus a continuous flow of oil into the well is maintained, thereby increasing the per diem amount of oil obtained from the well. Thus by maintaining a constant low fluid level in the well by removing the oil as it flows thereinto, it will be perceived that more oil will flow into the well than when there is an alternate high and low pressure in the well caused by allowing the same to head up and then pumping it olf. This is accomplished without the use of pumps or any other machinery, and through the utilization of the natural energ of the gas produced by the well itself. oreover, as indicated above, by closely spacing the stages of the gas lifts and controlling thev vent therefrom through the vent valve, the apparatus may be made to operate successfully in wells where the inflow of oil is great and the gas pressure therein is high, and still continue to operate successfully when the inflow of oil to the well is low and the gas pressure therein correspondingly diminished.

While the apparatus preferably employed in practicing the invention is herein described in detail, it is to be understood that the invention is not limited to the use of the particular apparatus. Furthermore, while such apparatus is shown and described herein, no claim is made to the same in this applieation, since it forms the subject matter of application Serial No. 112,405, filed May 28, 1926.

W'hat is claimed is:

1. The process of delivering liquid from an oil well which consists in closing the well and thereby confining therein the natural gas of the Well, utilizing the said confined gas to o erate under its own pressure a staged gas ift pump, and venting the exhaust from each stage against a controlled back pressure.

2. A process of delivering liquid from an oil well which comprises the steps of confining gas under ressure therein and constantly maintaining t ie combined pressure of suc confined gas and the head of oil in the well below that of the natural pressure forcing the oil into the well.

3. A process of continuously delivering liquid from an oil well which comprises the steps of confining the natural gas of the well therein, whereby the gas is subjected to the natural gas pressure in the sand, and constantly maintaining the combined head pressure of the oil in the well and the gas therein below the natural gas ressure by continuously removing oil and) gas from the well throu h a staged gas lift.

4. l process of continuously delivering liquid from an oil well which comprises the steps of confining the natural gas of the well therein, subjecting it to the natural gas pressure in the sand, passing the gas continuously through a staged gas lift thereb continuously removing oil from the wel and venting the gas from said gas lift against back pressure.

5. The process of delivering liquid from a well by installing therein a staged air lift pump in which the stage interval is determined by the air pressure used and the number of stages is determined by the depth of the well, closing the Well and subjecting the same to air pressure, and lowering, through removal, the normal stand of liquid in the well so 4that the pressure of the remaining stand plus the pressure of the air shall be less than the ressure of the normal stand of 1liquid on t e producing stratum in the we 6. The process of delivering liquid from an o1l well, which comprises the steps of confining the natural gas of the well under pres sure therein, constantly maintaining the" combined pressure of such confined gas and the head of oil in the well below that of the natural gas pressure forcing the oil into the well, and utilizing the confined gas under said pressure to lift the oil in the well in stages.

7. The method of operating an oil well, which consists in collecting the natural gas in the well, and keeping the resistance to inflow of oil to the well below that of the sand or natural gas pressure by continuously utilizing the gas to lift the oil in stages in the well and venting the gas from each stage against a controlled back pressure.

8. The process of continuously delivering liquid from an oil well, which comprises the steps of confining the natural gas of the well therein, whereby the gas is subjected to natural gas pressure in the sand, and constantly maintaining the combined head pressure of the oil in the well and the gas therein below the natural gas pressure by continuously removing oil and gas from the well in stages.

In testimony whereof I have signed this specification.

GEO.. BLOW. 

